Can someone explain to me how that works? I've only got a HD screen and that looks absolutely phenomenal!

Basically everything else you have been watching is a lower quality source. Saying it's HD is just a headline figure of how many pixels there are. There are all sorts of other factors that the picture quality will depend on - the quality of the camera, the quality of any editing/colour correction, the original light levels, the amount of compression applied etc etc. I have seen totally uncompressed HD video on a professional studio display and it looks better than what you get out of most TVs.

It was the same with VHS. When I first got a DVD player I copied a DVD to VHS on my fairly high end and well maintained VHS recorder and I was quite impressed with the results. It wasn't a patch on DVD quality but it was certainly far better than all the pre-recorded films I had been watching.

Can someone explain to me how that works? I've only got a HD screen and that looks absolutely phenomenal!

All video compression is the throwing out of data... if you are watching 1080p.. the data is being thrown out of the 1080 pixels. With this, the data that's being thrown out at the 8k scale is so small, it's not physically visible at 1080 scale.. so all your 1080 pixels is basically pure and uncompressed..

The first bits of data thrown out with video compression, even 4K HDR... is the colour information. Here.. you are using every single pixel of your 1920x1080 display getting the equivalent of uncompressed colour (1080p 4:4:4) that the original camera sensor output.

Same as showing a nice SLR camera still on your computer screen.. they look nicer than video frames..

True! I recently got a Sony Bravia 32" TV in a sale that has HDR but is a regular HD panel and not 4K (I can't physically fit a 40 or 43" 4K panel in my living room) the difference HDR makes in supported Youtube Content, Netflix and Gaming is astounding.

Bought a 4k HDR TV last year and a 4k Blu Ray player recently in the sales, it came with 4K discs of The Revenant, The Martian & Independence Day which wasn't a bad deal. Martian was substituted for a blu ray but a few calls to Samsung sorted that out....

I've been using a PS4 Pro until now which has done a good job, wasn't convinced it was worth the "upgrade", The Revenant looked great in 4k but not a big leap, Dunkirk arrived today which looks incredible!!!!

HDR is the difference, also noticing how good the colours are over the PS4 Pro on standard Blu rays.

I upgraded a month or so back, so got a small collection, bulked out by the Nolan 7-Film and Mission Impossible 5-film box sets.

Though have to say, as I went from a standard bulb based projector to a laser projector that the biggest benefit I'm seeing is actually in the brightness and contrast range, which also gives a nice boost to non-4K stuff.